Software features

Hemisfer is a software designed to estimate the leaf area index (LAI) and/or the local light regime from hemispherical photographs. It includes the following capabilities:

• It works on standard JPEG, TIFF, BMP, GIF or PNG files with 2, 8 or 24 bits per pixel.
• Single files can be handled interactively or large batches can be processed automatically.
• Beside true hemispherical pictures, wide-angle pictures can also be analysed (lens angle <90°).
• Information about the pictures can be stored in plain-text (understandable) INI parameter files and retrieved from there.
• It is also possible import HVS parameter files generated by HemiView, a software by Delta-T.
• The software can handle pictures in all common resolutions*.
• Knowing the location and the orientation of the picture, the software can calculate the light regime prevailing under the canopy at the point from which the picture was taken.
• Several known methods are available to estimate the LAI from the light transmission in rings around the zenith.
• There is the possibility to take the effect of the ground slope into account.
• Several algorithms are included to correct for their effect of large gaps in clumped canopies.
• The software is able to calculate the threshold to distinguish between white (sky) and black (canopy) pixels according to the γ (gamma) value of the picture.
• Results are saved in standard file formats, easy to import in softwares used for further processing (spreadsheets, statistical software, graphic software).

*The free downloadable software is limited to an image analysis within a radius of 500 pixels. This limitation is removed upon registration.